TY  - JOUR 
T1  - How to avoid bias in systematic reviews of observational studies
JO  - Revista CEFAC
A1  - Almeida, Carlos Podalirio Borges de
A1  - Goulart, Bárbara Niegia Garcia de
SN  - 1516-1846
UL  - 10.1590/1982-021620171941117
VL  - 19 
Y1  - 2017
PB  - Brasil 
ER  -